A registry and clinical study of patients with hereditary polyposis and colorectal cancer syndrome developed at the Johns Hopkins Hospital in 1973. Nine years later the Bowel Tumor Working Group was formed to study the pathobiology and molecular genetics of colorectal tumors. The Registry is maintained in a computerized Dbase IV database and includes: 1) family histories and food frequency questionnaires on patients evaluated for colorectal neoplasm and 2) families with a history of familial aggregation of colorectal cancer and early onset colorectal cancer and polyposis syndromes. The CORE was expanded in 1996 to collect similar data from pancreatic cancer patients. Currently, the CORE for Colorectal and Pancreatic Cancer collects family history, medical history, environmental/exposure data, and dietary data from affected and at-risk individuals and procures specimens from identified individuals to support investigation of familial and environmental factors and molecular genetic alterations in both colorectal and pancreatic cancer.